Propeller



E. c, BAKER March 7, 1939.

PROPELLER Filed Jail 31, 1938 INVENTOR Edward C. Baker WITNESSES v ATTORNEYS Patented Mar. 7, 1939 UNITED STATES PATENT OFFICE PROPELLER Edward C. Baker, Avenel, N. J.

Application January 31, 1938, Serial No. 187,865

TClaims. (01. 170-172 This invention relates to propellers, and more particularly, to' propellers adapted to displace fluid, such as water or air.

An object of the invention is to provide a pro- 5 peller which will displace a larger volume of fluid and thus have greater efliciency.

A further object of the invention is to provide a propeller with which it will be possible to control more accurately the direction of the fluid displaced.

While many propellers have been designed or constructed to cause greater displacement of fluid, many of them lose the efliciency which would be caused by greater displacement due to 15 the particular construction and the necessity of an increased motor powerin' their operation.

In the past, in order to increase displacement,

increased pitch for the entire blade has been used. After the pitch has been increased to a 20 certain degree,it' will cause a partial vacuum within its own circle and thus cut down the driving power. The present invention tends to overcome this difliculty and to enable a greater pitch without loss of driving power.-

25 The principal objective is, therefore, to provide a blade which will cause greater displacement with better direction without an undue increase in energy used. 7 1

My improved propeller is adapted to be made 30 of materials now in use, such as wood, alloys,

metal and similar materials.

In the accompanying drawing, Fig. 1 is a face view of my new propeller. Fig. 2 is an edge view and Fig. 3 is a cross-sectional view taken on the 35 line 3-3 of Fig. 1.

Referring more particularly to the drawing, the propeller l0 may be molded, or cast, depending upon the materials used, and consists of a hub I I, having an opening l2 therein to receive the pro- 4 peller shaft and a key seat l3 to flx the propeller with relation to the shaft, although other means may be used. Extending from the hub II are the blades II. The blades M are provided with longitudinal slots or openings l5 extending through 45 the heavier or trailing edge 22 of the'blade ll,

into approximately the center of the surface of said blade l4, and substantially at right angles with said trailing edge .22. These slots IS in eflect divide the blades I 4, so that the two contact 50 elements l6 and I! are provided in the working face of the blade. The contact element I1 is fixed at one angle to the propeller shaft, while the contact element It is so constructed that it meets the air at a different and greater angle. For the 55 purposes of strength and sturdiness, and in order to prevent undue vibration, these slots l5 do not extend the entire length of the blade, but are interrupted by solid portions l8. The solid portions I8 are streamlined to avoid resistance, and the two contact elements, l6 and I1 form an integral 5 tip, I9. The trailing edge 22 of the blade is much thicker than the leading edge 20. This not only increases the sturdiness of the blade but causes a greater displacement of air. In view of the extra thickness, the trailing edge 22 will be heavier than 1 the leading edge. While the propeller might be made in two parts, one consisting of the contact element l1 and the other of the contact element IE, it is believed that a sturdier and more practical propeller will result from casting the entire propeller in one piece, with the slots l5 therein, or by cutting the slots l5 out of one piece of material.

The rear element of the blade I4 is curved at 2| to cut down resistance, and prevent vacuum.

In operation, the cutting leading edge 20 of the blade I4 cuts into the fluid, forcing it against the contact elements I6 and I1. It will be noted that the fluid forced against the contact element I I will, after having passed over its element, proceed through the slots l5 and thus avoid the vacuum which would be caused by a propeller having the entire blade of the same pitch as the contact ele-v ment IS. The remaining fluid contacted by the blade l4 would be spilled against the contact element l6.

While in the drawing, I have illustrated a twobladed propeller, it will be understood that three or four blades might be used. Similarly, the blades might be shorter and broader where they are used for different purposes, and it will be appreciated that a blade used in the water would ordinarily be shorter than one used in the air,

I claim:

1. In a propeller having a high-pitched blade 40 with a leading and a trailing edge, means for preventing loss of efiiciency due to the degree of pitch, said means comprising apertures extending from the center of the face of said blade through the trailing edge, said apertures terminating short of the tip of said blade.

2. A propeller comprising a hub,'blades extending radially from said hub, each of said blades having a leading and a trailing edge, and being solid at their outer tip's, said trailing edge being substantially heavier than said leading edge, said blade tapering from said trailing edge to said leading edge, and a plurality of slots extending through said trailing edge into approximately the center of the working face of said blade.

3. A propeller blade having a leading and a trailing edge, said trailing edge being substantially heavier and thicker than said leading edge and said blade tapering from said trailing edge to said leading edge, one surface of said blade being streamlined from the leading edge to the trailing edge. and the other surface of said blade having slots extending from approximately the center thereof through said trailing edge, said blade .being solid adjacent its innermost and outermost ends.

4. A propeller blade having a leading and a trailing edge and'being substantially triangular V in cross section, said blade tapering from the trailing edge to the leading edge and having elongated slots extending through said trailing edge and substantially at right angles thereto, into the working face of said blade, said apertures being terminated short of the tip ofsaid blade.

5. A propeller blade having a leading and a trailing edge and being solid at its outer-end, said trailing edge being substantially thicker than said leading edge and said blade tapering from said trailing edge to said leading edge, one surface of said blade being streamlined from the leading edge to the trailing edge and the other surface of said blade having slots extending from approximately the center thereof through: said trailing edge. g

6; A propeller blade having a leading and trailing edge; said trailing edge being substantially thicker than said leading edge, and said blade tapering from said trailing edge to said leading edge, one surface of said blade being streamlined from the leading edge to the trailing edge, the other surface of said blade having a plurality of slots extending from approximately the center thereof through said trailing edge, and solid streamlined sections between said slots and between said slots and the tip of the blade.

7. A propeller blade having a leading and trail ing edge, said trailing edge being substantially thicker than said leading edge, and said blade tapering from said trailing edge to said leading edge, one surface of said blade being streamlined from the leading edge to the trailing edge, the other surface of said blade having a plurality of slots extending from approximately the center thereof through said trailing edge, and a solid portion extending between the edge'of the outermost of said slots and the end of the blade.

EDW. 0.. BAKER. 

